by tonyj » Sat Jun 01, 2013 9:46 pm
Depending on the poly resin you are using, many laminating resins do not require sanding between coats. Additional coats chemically bond to the previous coat. Final or finish coat should contain wax which makes a good hard sandable surface. Sanding laminating resin will gum sandpaper quickly, and you don't really want to build multiple layers of waxed resin because it does require that mecanical bond produced by sanding.
Instead of sanding those high spots or drips and runs between coats, use a scraper. (I am assuming you are using polyester resin and not epoxy, since you have used the term "fiberglass.")
Still graced with two eyes and ten fingers (due in no small part to luck!).
Just when you think a problem is solved, an uglier result replaces it.
tony